How long do you wait for a reduction in EBV viral load after reducing immunosuppression before deciding to start rituximab in a kidney transplant patient with EBV viremia?

This is a difficult question. If this is in the context of EBV viremia and kidney transplant patients with PTLD that is EBER positive, I make this decision in consultation with the treating hematologist/oncologist. I have not used rituximab in EBV viremia alone.